GB 13550—92 5A Molecular Sieve and Its Test Methods
Molecular sieves are crystalline metal aluminosilicates with a large internal pore surface and high selectivity for molecules or compound substances. The particles are mainly composed of silicon-aluminum oxides, and the pores on their surface are four-dimensional structures of 4, 5A, 6A and 10A rings. At present, molecular sieves (further divided into type A, type X and type E) are the first choice for adsorption and drying in modern industry due to their special structure, small size and good adsorption performance.
Molecular sieves 5A is one of the most common type among Molecular sieves, which is white crystal powders or block with internal micropore structure. It has a larger adsorption capacity than 3A molecular sieve, especially for polar molecules. So it is widely used in the adsorption drying and purification of ultra-pure liquids, such as oxygen and argon. Besides, it can also be used in the purification of solvents and aromatics.
This GB 13550—92 5A Molecular Sieves and Its Test Methods specifies the terms and definitions, classification, technical requirements, test methods and rules for inspection, packaging and storage of 5A molecular sieves.
1. Terms and Definitions
1.1 5A Molecular Sieve: Catalyst-free, permanent crystal powder or block used as an adsorbent.
1.2 Active Component: The component existing in crystalline form in the 5A molecular sieves material.
1.3 Clay Catalyst: Alumina support having a clay (hydrolized methylcellulose) catalyst covering on its surface.
2. Classification
2.1 Molecular Sieves 5A are classified according to the size of the holes and the particle size of the product.
3. Technical Requirements
3.1 Physical Requirements
3.1.1 The appearance of the product should be white and powdery, and the crystal should be solid in shape.
3.1.2 The product should be free from impurities, such as visible foreign matter, iron corrosion, black spots, etc.
3.2 Chemical Requirements
3.2.1 The active component of molecular sieves 5A should be ≥ 95%.
3.2.2 In the sample test, the total impurities should not exceed 3.0%.
3.2.3 The total alkali metals content should be ≤ 0.2%.
3.3 Technical Performance Requirements
3.3.1 The adsorption capacity of the 5A molecular sieves should be ≥ 6%.
3.3.2 The pressure drop should be ≤ 250 mbar.
3.3.3 The particle size should be 0.3mm—3.0mm.
3.3.4 The hole size should be 4—5A.
4. Test Methods
4.1 Sampling
4.1.1 The sampling method should be determined according to the actual situation, and the amount of sample should not be less than 2kg.
4.1.2 The sample should be stored in a sealed container during the transport process.
4.2 Test methods
4.2.1 Test the active components, total impurities, total alkali metals content, bulk specific gravity of the sample according to the Chinese national standard “Methods for Determination of Active Components, Total Impurities, Total Alkali Metals Content, Bulk Specific Gravity of Molecular Sieves”
4.2.2 Test the particle size of the sample using standard technical methods.
4.2.3 Test the hole size of the sample using standard technical methods.
4.2. 4 Test the adsorption of the sample using standard chemical adsorption methods.
5. Rules for Inspection, Packaging and Storage
5.1 Inspection
5.1.1 The company producing 5A molecular sieves should have sufficient quality assurance and inspection capacity to ensure the quality of the product.
5.1.2 The quality inspection and acceptance of the 5A molecular sieves should be carried out under the cooperation of the manufacturer and the buyer according to the regulations of Quality Inspection of Molecular Sieves 5A.
5.2 Package
5.2.1 5A molecular sieve should be in polyethylene lined cardboard barrels, blue plastic barrels or four-layer composite packaging bags for sealing, or other packages that were agreed between the supplier and the buyer.
5.2.2 The inner and outer surface of the packaging barrel should be clean, entire and no residue, and the accessories should be fastened tightly.
5.3 Storage
5.3.1 5A molecular sieves should be stored in a cool, dry and ventilated warehouse, avoiding the light and away from high-temperature sources, moisture sources, organic solvents, acids, alkalis and other substances.
5.3.2 Place the 5A molecular sieves away from the wall so as to avoid the high temperature generated by the sun striking on the wall.
5.3.3 The customized vehicles should be clean and tidy, the closing should be firm, the insulation should be good, and the accessories should be reliable.
5.3.4 During transportation, it should be prevented from wind and rain, sun, shock and bump.
5.3.5 5A molecular sieves should be stored within 1 year after production to ensure the best quality and performance of the product.
In conclusion, GB 13550—92 5A Molecular Sieves and Its Test Methods specified the terms and definitions, classification, technical requirements, test methods and rules for inspection, packaging and storage of 5A molecular sieves. It is the basic reference standard for the production, storage and use of 5A molecular sieves.
